Method and system for providing a therapeutic agent to an implanted infusion device

Abstract

A system for refilling a multi-chamber implantable infusion device is presented. The infusion device has a refill chamber which is accessible through an external septum of a refill port. The refill chamber is divided by an inner septum into an upper reservoir and a lower reservoir. The lower refill chamber is refilled with lower reservoir needles having a needle opening axially placed to align with the lower reservoir. The upper reservoir is refilled with an upper reservoir needle having an opening aligned with the upper reservoir. Magnetic portions are provided in the needles to localize and identify the needle. A processor within the infusion device is connected to magnetic field sensors which sense magnetic portions of the needle and recognize information encoded magnetically within the needle.

What is claimed is: 
     
         1 . A set of refill needles for an implantable infusion device, comprising:
 a lower chamber needle configured to refill a lower chamber of the implantable infusion device; and   an upper chamber needle configured to refill an upper chamber of the implantable infusion device,   the lower chamber needle and the upper chamber needle each having an elongated body extending from a proximal end to a distal end including a first magnetic portion arranged at a distance (d magnet1 ) from the distal end,
 wherein the first magnetic portion of the lower chamber needle has a first magnetic field orientation and the first magnetic portion of the upper chamber needle has a second magnetic field orientation different from the first magnetic field orientation, and/or 
 wherein the first magnetic portion of the lower chamber needle has a first magnetic field intensity and the first magnetic portion of the upper chamber needle has a second magnetic field intensity different from the first magnetic field intensity to encode a first bit of information, and 
 wherein the lower chamber needle has a lower needle opening positioned at a first axial distance from the distal end of the lower chamber needle, and 
 wherein the upper chamber needle has an upper needle opening positioned at a second axial distance from the distal end of the upper chamber needle, the second axial distance being greater than the first axial distance, and 
 wherein the first magnetic field orientation or the first magnetic field intensity identifies a refill needle from the set of refill needles as the lower chamber needle, and 
 wherein the second magnetic field orientation or the second magnetic field intensity identifies a refill needle from the set of refill needles as the upper chamber needle. 
   
     
     
         2 . The set of refill needles as in  claim 1 , wherein a first magnetic field of the first magnetic portion is axially oriented. 
     
     
         3 . The set of refill needles as in  claim 1 , wherein the first magnetic field is radially oriented with magnetic poles arranged radially inwardly and outwardly of one another. 
     
     
         4 . The set of refill needles as in  claim 1 , wherein the first magnetic field is diametrically oriented with magnetic poles arranged circumferentially opposite one another. 
     
     
         5 . The set of refill needles as in  claim 1 , wherein each elongated body is made of molded plastic and wherein the first magnetic portion is formed by a permanent magnet overmolded within the plastic. 
     
     
         6 . The set of refill needles as in  claim 1 , wherein each elongated body includes a plurality of two or more magnetic portions, each of the two or more magnetic portions being selectively magnetic in a first magnetic field orientation or a second magnetic field orientation to store one bit of information.